In the older days they would just get a visit, now naming and shaming them on the internet seems to be the tool of choice. I'd name and shame them then see it for what it is, crap on the internet to be ignored and carry on as usual doing what you do, doing your own thing

Ciri, if you know who they are and you don't feel safe about naming them, PM me with whatever info you have and I'll see if there's anything I can do.(Probably not, but ya never know, and at least I will know to be watchful.)